On My 2022 Camry Hybrid the back middle seatbelt alarm (Intermittently) beeps when no one is in it so I just buckled the seatbelt. Now the rear passenger side seatbelt is doing the same thing, driving me nuts! The local Toyota dealership says there's nothing they can find that is wrong. They are doing their best to get me to go away, and it's making me mad as hell. I suspect this is a manufacturer known defect. Any advice or help would be appreciated. Thank you in advance

 

Did you try to buckle the belt on the seat that is giving the new alarm?

Each seat may have an occupant sensor the responds to weight on the seat The sensor could have a problem.

The false alarms appear common.

Can only guess as to why the dealer is distancing you. Suspect its too much work and expense to deal with and as you state they hope you will go way.

When the alarm is going off have someone seat in the seat with the belt off. Determine if the alarm stops.

 

To my understanding seat belt sensor activates based on pressure mat underneath the seat cushion,

You can try the following
1. Check for spilled/liquid damage on seat[use a wet shop vac or those vacs at car wash] , inspect the rear cushion is the rear seat cushion compressed?
2. Get someone people to sit in the back seat , or gently bob/fluff up the seat to change the sensor state, this may free the sensor
3. Note the time/place of sensor going off (if its hot or cold inside) ,go back to dealer since you are under warranty or try another dealer if they arent willing to helping you